What is an action and how can I use it in a workflow?

You can think of Automations as a series of events that you prepare beforehand so that they engage your mailing list while you're busy working on other things; they're a life-saver! Which means that it's very important to make sure that what happens in an Automation is setup correctly before the Automation is launched. Actions are the pieces of your Automation Workflow which handle the "what happens" part and they can be set up at any point during your workflow, as long as you've first set the Automation Trigger that sets things in motion.